RESUMEN
The retroviruses are a large, diverse family of enveloped RNA viruses defined by their structure, composition and replicative properties. The hallmark of the family is its replicative strategy, essential steps of which include reverse transcription of the viral RNA and the subsequent integration of this DNA into the genome of the cell. These steps are performed by two viral-encoded enzymes, reverse transcriptase (RT), which possesses DNA polymerase and ribonuclease H (RNase H) activities, and integrase (IN). These enzymes are excellent targets for retroviral therapy since they are essential for viral replication. Numerous substances capable of inhibiting the DNA polymerase activity of HIV-1 RT are available, while few specific inhibitors of RNase H activity have been described. IN is absolutely necessary for stable and productive infection of cells. Some IN inhibitors have been recently reported and are available demonstrating the potential of IN as an antiviral target. This paper is an overview of the inhibitors of RNase H and IN and describes the most promising inhibitors.
Asunto(s)
Fármacos Anti-VIH/farmacología , Diseño de Fármacos , Infecciones por VIH/tratamiento farmacológico , Inhibidores de Integrasa VIH/farmacología , Integrasa de VIH/efectos de los fármacos , Transcriptasa Inversa del VIH/efectos de los fármacos , VIH-1/efectos de los fármacos , Inhibidores de la Transcriptasa Inversa/farmacología , Ribonucleasa H/antagonistas & inhibidores , Fármacos Anti-VIH/química , Fármacos Anti-VIH/uso terapéutico , Línea Celular , Evaluación Preclínica de Medicamentos , Integrasa de VIH/química , Integrasa de VIH/fisiología , Inhibidores de Integrasa VIH/química , Inhibidores de Integrasa VIH/uso terapéutico , Transcriptasa Inversa del VIH/química , Transcriptasa Inversa del VIH/fisiología , VIH-1/enzimología , VIH-1/fisiología , Humanos , Proteínas Recombinantes de Fusión/antagonistas & inhibidores , Inhibidores de la Transcriptasa Inversa/química , Inhibidores de la Transcriptasa Inversa/uso terapéutico , Ribonucleasa H/química , Técnica SELEX de Producción de Aptámeros , Saccharomyces cerevisiae , Integración Viral/efectos de los fármacos , Replicación Viral/efectos de los fármacosRESUMEN
Six affinity reagents containing chemically reactive groups, either on the phosphate residue at the 5'-end or on the 5'- or 3'-end internucleoside phosphate linkages of the oligothymidylate primers, were used to covalently modify the human immunodeficiency virus type 1 reverse transcriptase (HIV-1 RT). After covalent binding of these modified primer analogs to the enzyme, the addition of [alpha-32P]dTTP, in the presence of a complementary template, led to elongation of the primer. This reaction was catalyzed by the active site of the enzyme carrying the covalently bound primer. The relative efficiency of labeling of the p66/p51 heterodimer compared to the p66/p66 and p51/p51 homodimers of HIV-1 RT was in agreement with the previously determined affinity of the various enzyme forms toward different primers. The analogues preferentially modified the p66 subunit of the HIV-1 RT heterodimer. The labeling of all RT forms by synthetic primer analogues showed significant and specific competition by the natural primer of HIV-1 RT, tRNA(Lys). In addition, the kinetics of inactivation of RT by primer analogues was studied. The affinity of the enzyme to those derivatives in the presence of poly(A) template was about 5-10 times higher than in the absence of template. Moreover, the maximal rates of HIV-1 RT inactivation by analogues in the absence of template were 3-4 times higher. Our results suggest that the mechanism of oligonucleotide primer binding to HIV-1 RT is different in the presence or absence of template.(ABSTRACT TRUNCATED AT 250 WORDS)